JPS631376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for cooling a hot steel plate in a hot rolling line or a heat treatment line for steel plates, and an apparatus used therefor.

[Prior art]

Conventionally, when cooling such hot steel plates,
Depending on the purpose, methods are adopted, such as spraying cooling water, using slits or pipe laminators, installing an immersion weir on the line and passing the hot steel plate through cooling water, and using close spray nozzles. ing.

However, methods that spray cooling water, use slits or pipe laminators, or install an immersion weir in the line and pass the hot steel plate through cooling water have a narrow control range of cooling capacity. Due to the structure of the equipment used for this purpose, there are many drawbacks such as the tendency for the shape of the steel plate to deteriorate, so it is only used for some special purposes.

On the other hand, the method using close spray nozzles has a wide range of control over the cooling capacity, and as shown in Japanese Patent Publication No. 47-46641, the deterioration of the shape of the steel plate has been considerably improved. This method has been widely adopted in recent years.

However, with this cooling method, there is a difference in the phenomenon of stagnation of the cooling water injected from the spray nozzle onto the steel plate, which is the material to be cooled, between the front and rear ends of the steel plate and the center of the steel plate. The tip and rear ends have the disadvantage that the temperature of the steel plate is lower than that of the center and that warping is likely to occur.

This phenomenon will be explained based on FIG. When the heated steel plate 1 enters the cooling device, the water jetted from the lower spray nozzle 4b arranged between each roll of the conveyor roll 2 collides with the lower surface of the steel plate 1 and immediately falls, but each of the presser rolls 3 After the water jetted from the upper spray nozzle 4a arranged between the rolls collides with the upper surface of the steel plate 1, it remains on the steel plate as surface water.
Since the water on the plate between the respective rolls of the presser roll 3 only falls from both ends of the steel plate, the amount of water on the plate remains in the center of the steel plate in the state shown as 5a. On the other hand, in the case of the tip or rear end of the steel plate 1, since it falls from the tip or rear end at the same time from both side edges of the steel plate, residual plate water 5b remains at the tip or rear end of the steel plate. The amount is smaller compared to the central portion.

Fig. 2 shows the height H of the remaining amount of water on the plate and the steel plate 1 of the spray water sprayed from the upper spray nozzle 4a.
The relationship with surface impact pressure is shown. It can be seen from the figure that the collision pressure is greatly influenced by the water height H above the plate. This means that the impact pressure of the spray water will be lower at the tip or rear end of the steel plate where the residual height H of the plate water 5b is low and at the center where the residual height H of the plate water 5a is high, as shown in FIG. This shows that this causes a difference in the cooling capacity of each part of the steel plate.

That is, the front or rear end of the steel plate is cooled more rapidly than the center. The remaining height H of the plate water 5, which affects the cooling ability of the spray water, is:
Since it changes depending on the amount of spray water used Q, the width of the steel plate, and the roll pitch P, these are the factors that ultimately change the cooling capacity of this type of steel plate cooling device.

[Purpose of the invention]

An object of the present invention is to provide a cooling method and apparatus for uniformizing the temperature in the longitudinal direction of a steel plate and obtaining a well-shaped steel plate by paying attention to the above-mentioned phenomenon.

[Structure of the invention]

The present invention tracks and manages the position of a hot steel plate in a hot steel plate cooling device, and uses the tracking information to control forward or backward movement of a shielding plate for spray liquid at a position where the leading or trailing end of the hot steel plate is reached.

[Example] An example of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is an overall configuration diagram of the cooling device of the present invention, and FIG.
The figure is a cross-sectional view of the spray shielding device, Figure 5 is a plan view of the shielding plate and the cylinder for driving the shielding plate, Figure 6 is an explanatory diagram of the open and closed states of the shielding plate, and Figure 7 is the cooling calculation. FIG. 8, which is a diagram showing an example of the configuration of the control device, is a time chart for explaining the shielding plate control.

Reference numeral 6 indicates the entire cooling device, which is installed in a hot steel sheet conveyance line and includes a conveyance roll 2, a presser roll 3, a spray nozzle 4, a header 7, and a spray blocking device 10.

Reference numeral 8 indicates a steel plate entry detector provided on the entry side of the hot steel plate 1 of the cooling device 6, and 9a and 9b indicate thermometers for detecting the temperature of the steel plate installed on the entry and exit sides of the cooling device, respectively. It is.

As shown in detail in FIG. 4, the spray shutoff device 10 is installed between the spray nozzle 4 between the rolls 2 and 3 and the steel plate pass line 15, in the vertical direction of the steel plate pass line 15, and between the spray nozzle 4 between the rolls 2 and 3 and the steel plate pass line 15. They are arranged at intervals, and are composed of a shielding plate 12, a cylinder 13 for driving the shielding plate, and an apron 11. The apron 11 prevents damage to the spray nozzle 4 when the steel plate 1 warps, and has a protrusion 14 for holding the shielding plate 12, and is fixed to the main body (not shown) of the cooling device. There is.

Further, each of the apron 11 and the shielding plate 12 has a pitch a of the nozzle 4 shown in FIG.
A plurality of spray holes 16 and 1 are arranged at intervals matching the
7 is provided. The shielding plate 12 is configured to be capable of reciprocating movement by a cylinder 13 for driving the shielding plate, and the cylinder 13 for driving the shielding plate
is the shielding plate on/off timing control mechanism 2, which will be described later.
2, the apron spray hole 16 and the shielding plate spray hole 17 are moved from the open state shown in FIG. 6a to the closed state shown in FIG. 6b, and from the closed state to the open state. The shielding plate 12 is configured to move by a/2 pitch.

FIG. 7 is a block diagram showing a cooling calculation and control device for controlling the opening/closing movement of the shielding plate 12.

In the same figure, 20 indicates the steel type and thickness of the hot steel plate;
This is a cooling control mechanism that controls the cooling capacity of the entire cooling device by calculating the amount of cooling liquid, the speed of sheet passing through the cooling device, etc. based on the board width, board length, entrance temperature, etc. 21 is the number of shielding plates used according to the command of the cooling control mechanism 20;
This is a shielding plate control calculation mechanism that calculates the combination control of the upper and lower shielding plates, the closing timing, etc. 23 is plate length information given from the cooling control mechanism 20,
Based on the steel plate tracking start signal obtained from the steel plate entry detector 8 and the conveyor table passing speed information obtained from the rotation speed detector provided on the conveyor table in the cooling device, the positions of the leading and trailing ends of the steel plate 1 are determined moment by moment. This is a steel plate position tracking management mechanism. Reference numeral 22 denotes a shielding plate on/off timing control mechanism that controls opening and closing of a specific shielding plate at the commanded timing based on the commands of the shielding plate control calculation mechanism 21 and the steel plate position tracking management mechanism 23. 24 is a shielding plate operation performance management mechanism that detects the performance of the shielding plate and feeds it back to the cooling control mechanism 20.

The operation of each shielding plate is performed based on a predetermined program based on the calculation results of the cooling control mechanism 20 and the shielding plate control calculation mechanism 21.

FIG. 8 shows a time chart for opening/closing control in the case of five shielding plates A, B, C, D, and E. In the figure, the upper view shows the passing time of the steel plate at the position of each shielding plate, and the lower diagram shows the open/closed state of each shielding plate corresponding to each passing time. The vertical axis L indicates the distance from the entrance side of the cooling device 6 shown in FIG. 3, and the horizontal axis indicates the elapsed time T after the steel plate 1 enters. The shielding plates A and B provided at L ₁ and L ₂ are used to shield the front and rear ends of the steel plate, and the control timing is such that the front end of the steel plate is Tt ₁ +ΔTt ₁ and Tt ₂ +ΔTt ₂ , and the steel plate The rear end portions are Tb ₁ -ΔTb ₁ and Tb ₂ -ΔTb ₂ . In addition, the shielding plate C provided at a distance L ₃ is
It is used to block only the tip of the steel plate, and the control timing is
Tt ₃ +ΔTt ₃ , the shielding plate D provided at a distance L ₄ is used to shield only the rear end of the steel plate, and the control timing is Tb ₄ −ΔTb ₄ . Further, the shielding plate E provided at a distance L ₅ is not used for shielding the front end and the rear end, and is always open while the steel plate 1 is in the cooling device 6 .

The entry of the hot steel plate 1 into the cooling device 6 is detected by a signal from the steel plate entry detector 8, and the steel plate position tracking management mechanism 23 grasps the steel plate leading and trailing edge positions from time to time, and the shielding plate on/off timing control mechanism 2
The signal is input to 2.

Next, a method of controlling the shielding plate will be explained.

First, at the time Tti during which the tip of the steel plate advancing at the plate threading speed V enters the cooling device 6, the driving cylinders 13 of the shielding plates D and E, which are not used for blocking the tip of the steel plate, are activated to D and E are changed from the closed state shown in FIG. 6b to the open state shown in FIG. 6a.

Next, when the tip of the steel plate reaches the installation position L ₁ of the shielding plate A, in order to block the tip of the steel plate by the distance V・ΔTt ₁ with the shielding plate A, the shielding plate is driven for a time of Tt ₁ +ΔTt ₁ . The cylinder 13 is operated to open from closed.

Next, the tip of the steel plate is at position L ₂ of shielding plates B and C.
When reaching L ₃ , the shielding plates B and C are opened from closed at times Tt ₂ +ΔTt ₂ and Tt ₃ +ΔTt ₃ in the same way as the shielding plate A.

As the steel plate advances further and the rear end of the steel plate reaches around position L ₁ of shielding plate A, the rear end of the steel plate is moved by a distance V・ΔTb ₁
The shielding plate drive cylinder 13 is operated at a time Tb ₁ −ΔTt ₁ to control the shielding plate from open to closed.

Similarly, the rear end of the steel plate is at position L ₂ of shielding plates B and D.
When reaching around L ₄ , the shielding plates B and D are controlled from open to closed at times Tb ₂ -ΔTb ₂ and Tb ₄ -ΔTb ₄ .

Finally, the time when the trailing edge of the steel plate is extracted from the cooling device
At tb ₀ , the shielding plates C and E, which are still open, are changed from open to closed.

In the above explanation, there is no distinction made between the shielding plates A to E for the top surface and the bottom surface of the steel plate, but for example, if the shielding plates are thick and cannot be expected to be effective by shielding only the top surface, or if they are provided on both the top and bottom, the entire surface can be covered. In order to reduce the number of shielding plates, it is also possible to install them on both the upper and lower sides.

Moreover, the shielding plates may not be provided between all the rolls in the cooling device, but may be provided at certain intervals, or may be provided in specific zones.

I explained that the nozzle hole of the shielding plate is fully open and fully closed, but
By adjusting the distance of forward and backward movement, the amount of coolant can be arbitrarily controlled.

As the coolant, water or water to which a rust preventive agent is added is used.

In addition, the combination of the steel plate tip and rear end shielding of shielding plates A, B, C, D, and E and the shielding distance ΔT・V are as follows:
The longitudinal temperature deviation and shape of the steel plate after cooling are controlled to be optimal by the size of the heated steel plate, cooling pattern, pre-cooling temperature pattern, etc.

〔Effect of the invention〕

The effects of the present invention are listed below.

(1) Uniform cooling can be achieved over the entire length of the steel plate.

(2) Through (1) above, a steel plate with uniform overall length can be obtained.

(3) According to (1) above, a steel plate with good shape can be obtained over the entire length of the steel plate.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional type proximity spray type cooling device, Fig. 2 is a diagram showing the relationship between the water height above the plate and the spray impingement pressure, Fig. 3 is an overall configuration diagram of the hot steel plate cooling device of the present invention, and Fig. 4 The figure is a cross-sectional view of the spray shutoff device.
FIG. 5 is a plan view of the shielding plate and the cylinder for driving the shielding plate, FIG. 6 is an explanatory diagram of the open and closed states of the shielding plate, and FIG. 7 is a diagram showing an example of the configuration of the cooling calculation and control device. FIG. 8 is a time chart for explaining the shielding plate control. DESCRIPTION OF SYMBOLS 1... Hot steel plate, 2... Conveyance roll, 3... Opposing presser roll, 4... Spray nozzle, 5... Board water, 6... Cooling device, 7... Header, 8...
Steel plate entry detector, 9... Steel plate thermometer, 10... Play blocking device, 11... Apron, 12... Shielding plate, 13... Shielding plate driving cylinder, 14... Protrusion, 15... Steel plate pass line, 16... Spray hole in apron, 17... Spray hole in shielding plate, 20... Cooling control mechanism, 21... Shielding plate control calculation mechanism, 22... Shielding plate on/off timing control Mechanism, 23... steel plate position tracking management mechanism, 24... shielding plate operation performance management mechanism.

Claims (1)

[Claims] 1. A method of injecting liquid into a heated steel plate while pressing it from above and below with rolls, comprising: providing means for controlling the amount of cooling liquid passing above and/or below between the rolls, and further controlling the passing position of the heated steel plate. A method for cooling a hot steel plate, comprising: providing a detection means and a cooling calculation control means, and controlling the amount of cooling liquid passing through a position where the leading end and/or rear end of the moving hot steel sheet is about to pass. . 2. A hot steel plate cooling device in which a plurality of presser rolls are arranged at paired positions above a conveyance roller table on a hot steel plate conveyance line, and hot steel plate cooling nozzles are arranged above and below between the presser rolls. A shielding plate for controlling the amount of cooling liquid from the nozzle is attached above and/or below between the nozzle and the pass line of the hot steel plate so as to be movable forward and backward in a direction perpendicular to the traveling direction of the hot steel plate, and a forward/backward distance control mechanism is provided. is provided and connected to the shielding plate, a hot steel plate detector and a cooling calculation control device are provided and connected, and the cooling calculation control device and the advance/retreat distance control mechanism of the shielding plate are connected. Heat steel plate cooling equipment.